Backpack rear portion



FIG. 1 is a side, rear, perspective view of the backpack rear portion with rearwardly facing shoulder straps and a front portion of the backpack shown in phantom;

FIG. 2 is a rear view thereof;

FIG. 3 is a front view thereof;

FIG. 4 is a right side view thereof;

FIG. 5 is a left side view thereof;

FIG. 6 is a top view thereof; and,

FIG. 7 is a bottom view thereof.

The broken lines shown throughout the views illustrate the environment in which the design exists, and forms no part of the claimed design. Any surfaces which are not shown in solid lines are not part of the claimed design. 

The ornamental design for a backpack rear portion, as shown and described. 